VOGONS


First post, by AlessandroB

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I came into possession of an intact IBM 5150, exactly as it left the factory, with 64 / 256k mainboard, latest BIOS revision, Monitor 5151 and the coordinated IBM printer.
Since everything is perfectly preserved, and working, I thought of studying this system and seeing what it is possible to achieve, comparing it to the systems that succeeded it.
Reading on the internal components (only the MDA graphics card and the controller card for the two floppy drives) I understood that in order to use it in a profitable way it is necessary to expand it. At this point, however, I wondered how much of the correct period system remained...
The components that according to my analysis are to be expanded are the following:

1)Video Card. The video card is probably the fundamental component since the serial card is only capable of drawing characters and no graphics. So I chose an excellent card, an ATI wonder 16, this card is capable of driving the 5151 monitor as CGA graphics and also has a 15 pin output for EGA and VGA as well as a mouse port.

2)Hard disk, the mfm disks of the time I know are quite fragile and noisy and in addition I did not want to remove one of the two floppy drives because I consider the most characteristic dual player and keeps the shape of the computer more faithful to the original. porendero an xt-cf lite v4 card. This is the only modern component but I think in this case it is more important than the correct period also considering that the serial computer had no hard disk (also considering the low amperage of the power supply).

3)RAM, as standard I only have 64Kb which is too little for almost anything, I will have to get the chips to expand the mainboard to the maximum plus another ram expansion card to bring it to 640 or 512, this I have not yet understood...

4)CPU, standard mounts an 8088 at 4Mhz, already at the time it was replaced with a NECV20 and in addition there is a chip to put in place of the chip that generates the frequency to bring the cpu to 8Mhz. Both the CPU and the coupon should be correct period

5)At this point, only 1 of the 5 ISA slots remains free (MDA-VGA-Floppy controller-XT-CF). I thought of taking a sound card of the time, I have a sound blaster 2.0 it may be too recent but perhaps not much.

What do you think of my thoughts on the correct period and on the reasons for being bordeline on the correct period? I want to clarify that any modification is reversible and at any time the computer can be restored to 100% original. No physical changes are made.

Reply 1 of 23, by waterbeesje

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To stay period correct these mods seem legit more or less.

CGA was the original upgrade from MDA, so possible indeed. For correctness a Hercules card would be more logical as these became available not long after the pc XT (still period correct on a 5150 if you kept it for years).
The VGA Wonder 16 would be a bit too new if you ask me... But for compatibility this is an excellent choise.

For a hard disk the xt IDE solutions are reliable and relatively easy to get. Also it eliminates the issues to transfer software from more modern computers. As you said: reliable mfm hard disks are not easy to find, and would require to remove a floppy drive.

Memory upgrade to 256kB was already on Santa's list. All the way up to 640kB ... Most people did not dare to dream about it before a few years. But it was certainly possible and a few geeks with unlimited bank cache probably had this quite soon. Or if you kept it for a few more years and wanted to use demanding software. EMS would be in reach then as well.

CPU could become a V20 to get more instructions but I would not get it to 8MHz. Stay at 4,77 and keep full compatibility with specific software. If you really want to upgrade you could look into a 286 or 386 upgrade card.

Sound on a 5150 would be a waste, as there is not much software that an use a 8088 and sound at the same time. Instead an EMS upgrade or CPU upgrade card would make more sense to me.

Stuck at 10MHz...

Reply 2 of 23, by AlessandroB

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waterbeesje wrote on 2020-07-25, 09:42:
To stay period correct these mods seem legit more or less. […]
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To stay period correct these mods seem legit more or less.

CGA was the original upgrade from MDA, so possible indeed. For correctness a Hercules card would be more logical as these became available not long after the pc XT (still period correct on a 5150 if you kept it for years).
The VGA Wonder 16 would be a bit too new if you ask me... But for compatibility this is an excellent choise.

For a hard disk the xt IDE solutions are reliable and relatively easy to get. Also it eliminates the issues to transfer software from more modern computers. As you said: reliable mfm hard disks are not easy to find, and would require to remove a floppy drive.

Memory upgrade to 256kB was already on Santa's list. All the way up to 640kB ... Most people did not dare to dream about it before a few years. But it was certainly possible and a few geeks with unlimited bank cache probably had this quite soon. Or if you kept it for a few more years and wanted to use demanding software. EMS would be in reach then as well.

CPU could become a V20 to get more instructions but I would not get it to 8MHz. Stay at 4,77 and keep full compatibility with specific software. If you really want to upgrade you could look into a 286 or 386 upgrade card.

Sound on a 5150 would be a waste, as there is not much software that an use a 8088 and sound at the same time. Instead an EMS upgrade or CPU upgrade card would make more sense to me.

First of all thanks for the answer, I am happy to deal with those who are more prepared, it is very little time that I am interested in the original IBM PC series.

ATI Wonder 16 i think it can open up a world of experimentation, and anyway I don't think it's a wrong update as it came out 7 years after the first 5150 and the fact of maintaining compatibility with the 8 bit bus and TTL 9 Pin output indicates that this card is also made thinking to my 5150.

What do you mean by: "EMS would be in reach then as well"

Your consideration on the CPU interested me very much, I didn't think there were expansion cards to be able to mount a 286 or a 386 inside a 5150. Did you look for them for sure! Do you want to talk a little more about these 286/386 cards about features / limitations? Do you have any idea of their cost nowadays? And where i can find?

With a 286/386 card the sound could return to be interesting in my opinion ... free slot allowing ...

Reply 3 of 23, by waterbeesje

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With the ems i mean expanded memory, on another ISA adapter card to upgrade memory above 640kB. There are lots of internet pages that describe it better than I can, for example: https://en.m.wikipedia.org/wiki/Expanded_memory#EMS

There are ISA adapter cards that allow a 286 or 386 CPU to work on pc or xt class hardware. For example the Orchid Tiny Turbo got you to a 286 and the Intel Inboard PC even a 386. Those can work along with the original hardware an motherboard, but take up an ISA slot. You'll still be limited to the 8bit hardware you are using, but with a faster cpu and more memory. Also don't expect to get the full 286/386 experience, as this is merely some hybrid solution.
Might be a bit expensive and hard to find... These are collectors items.

Stuck at 10MHz...

Reply 4 of 23, by jesolo

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My 5 cents worth:

1) If you want to upgrade your video card, try and find a Hercules or compatible graphics card as this is capable of driving the 5151 MDA monitor. Take note that the IBM 5151 monitor is not CGA compatible. If you try and drive a CGA card via this monitor, you risk damaging the monitor, since CGA runs at a different horizontal refresh rate than MDA.

2) An XT-IDE card connected to a CF card is the best alternative in this case if you wish to retain the two floppy disk drives, but you also want the flexibility of having "fixed" storage.

3) First try and upgrade the conventional memory to 256K and then try and obtain a memory expansion card that will allow you to extend your memory to 640K. However, some memory expansion cards (like the Memo-576) allowed you to extend your conventional memory straight from 64K to 640K (provided that you populated the memory expansion card with the correct chips). EMS (expanded) memory is totally different matter.

4) Upgrading the CPU to an NEC V20 8 MHz (or higher) is not going to give you that much of a performance boost (but you will get a slight boost) since the clock crystal on the motherboard will still run the CPU at 4.77 MHz (regardless of the rated speed of the CPU). Also take note that there are sometimes compatibility issues when you replace the CPU with an NEC V20 - refer http://www.vcfed.org/forum/showthread.php?456 … 88-2-or-NEC-V20.

5) I wouldn't bother with sound, since most games that can run satisfactory on this type of hardware didn't support any sound. However, if you wish, you can install an Adlib or compatible clone in there for FM synthesis music playback.

Refer here for more info on possible upgrades and limitations: http://minuszerodegrees.net

Reply 5 of 23, by Anonymous Coward

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CGA wasn't really an "upgrade from MDA". The CGA was blurry in 80 column mode, and the interlaced graphics were headache inducing. The MDA on the other hand produced clear and crisp 80 column text and was easy on the eyes due to the slow phosphor. The CGA option was more consumer oriented, and the MDA option was for business. You could actually have both monitors and cards installed at one time and they wouldn't conflict. In my opinion the Hercules option was the best of both words. CGA was barely colour anyway if you used the 5153 (4 crappy colours in graphics mode to be precise)...well unless you used an even blurrier composite display or a TV.

BTW, the 5150 wasn't designed for a hard drive. The power supply is only 63.5W. A full height MFM drive would choke it. A half height MFM drive is technically doable but I consider it risky especially if the power supply hasn't been serviced. Modern 3.5" drives should be safe...hardcards were a common upgrade for 5150s. Personally, I like the dual full height floppy setup with a CF card hidden at the back.

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Reply 6 of 23, by maxtherabbit

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I love my 5150, it's a really cool vintage computer

MDA is perfectly adequate, hercules if you insist on graphics

IMO it's not a gaming machine, enjoy it for what it is

Reply 7 of 23, by jesolo

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maxtherabbit wrote on 2020-07-25, 18:04:

IMO it's not a gaming machine, enjoy it for what it is

I second that.

Personally, I prefer the 5160 over the 5150 (I have both, however), but that's a topic for another discussion.

Reply 8 of 23, by AlessandroB

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jesolo wrote on 2020-07-25, 16:28:
My 5 cents worth: […]
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My 5 cents worth:

1) If you want to upgrade your video card, try and find a Hercules or compatible graphics card as this is capable of driving the 5151 MDA monitor. Take note that the IBM 5151 monitor is not CGA compatible. If you try and drive a CGA card via this monitor, you risk damaging the monitor, since CGA runs at a different horizontal refresh rate than MDA.

2) An XT-IDE card connected to a CF card is the best alternative in this case if you wish to retain the two floppy disk drives, but you also want the flexibility of having "fixed" storage.

3) First try and upgrade the conventional memory to 256K and then try and obtain a memory expansion card that will allow you to extend your memory to 640K. However, some memory expansion cards (like the Memo-576) allowed you to extend your conventional memory straight from 64K to 640K (provided that you populated the memory expansion card with the correct chips). EMS (expanded) memory is totally different matter.

4) Upgrading the CPU to an NEC V20 8 MHz (or higher) is not going to give you that much of a performance boost (but you will get a slight boost) since the clock crystal on the motherboard will still run the CPU at 4.77 MHz (regardless of the rated speed of the CPU). Also take note that there are sometimes compatibility issues when you replace the CPU with an NEC V20 - refer http://www.vcfed.org/forum/showthread.php?456 … 88-2-or-NEC-V20.

5) I wouldn't bother with sound, since most games that can run satisfactory on this type of hardware didn't support any sound. However, if you wish, you can install an Adlib or compatible clone in there for FM synthesis music playback.

Refer here for more info on possible upgrades and limitations: http://minuszerodegrees.net

1)why not use the card I mentioned? it is extremely flexible and can simulate cga on monitor 5151 on the correct output (9pin), plus many other standard graphics / monitor combinations

3)correct me if it is wrong: first populate all the 256k on the mainboard, second add 384kb on the separate isa card, third add ems, how?

4)there is a small card made in the mid 80's that connects instead of the clock generator and makes the 8mhz v20 cpu work, it's a nice performance jump isn't it?

Reply 9 of 23, by jesolo

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AlessandroB wrote on 2020-07-25, 21:19:

1)why not use the card I mentioned? it is extremely flexible and can simulate cga on monitor 5151 on the correct output (9pin), plus many other standard graphics / monitor combinations

Check the monitor's 9-pin connector. You'll see that pins 3, 4 & 5 are missing. It cannot accept a CGA signal. If you try and push through a CGA signal to the 5151 monitor, you can damage the monitor.
However, based on my understanding, some of the ATI wonder series cards could be configured to support Hercules mode, which will then provide you with both a graphics & text mode. I'm not that familiar with the ATI Wonder cards, but it's possible that it could also output CGA to a monochrome monitor, so long as it outputs at the proper frequency (which in this case must be around 18.432 kHz).

AlessandroB wrote:

3)correct me if it is wrong: first populate all the 256k on the mainboard, second add 384kb on the separate isa card, third add ems, how?

That depends what memory expansion card you have. Since the IBM PC is so slow, it doesn't really matter whether you populate the memory on the motherboard or on a RAM expansion card. However, you mentioned earlier that your motherboard has the latest BIOS revision. Due to some bugs in that BIOS revision (refer http://minuszerodegrees.net/5150/ram/5150_ram_64_256.htm & http://minuszerodegrees.net/5150/misc/5150_27 … 4_ram_banks.htm), it is advisable to first populate all 4 banks on the motherboard and then extend the memory with a memory expansion card up to 640K.
You can have a look here at an EMS memory card: https://www.lo-tech.co.uk/product/2mb-ems-board-pcb/. There might also be some people on Amibay that alread sells these complete or are willing to solder one together for you. However, take note that not many applications (that can run on this hardware) made use of EMS memory so, you might just be wasting your money.

AlessandroB wrote:

4)there is a small card made in the mid 80's that connects instead of the clock generator and makes the 8mhz v20 cpu work, it's a nice performance jump isn't it?

True, but then you are moving further and further away from the original hardware. I wouldn't bother upgrading a 5150 with an NEC V20 CPU. I would keep it stock standard and perhaps just add an XT-IDE interface card connected to a CF card. If you want a faster XT PC, then try and obtain an IBM clone motherboard (like a Juko ST) that came with an NEC V20 CPU.

Reply 10 of 23, by AlessandroB

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1) The ATI wonder that I took from what I read can drive MD monitors directly by simulating up to EGA. Then I read the manual better.

2)ok, I understand that to have the EMS you need to add an additional card. But the memory between the basic 640k and the first mega (380), are part of this expansion card like the one you linked to me? I used to think like in the days of the 486 that had 4 megs of ram and all the different portions of ram were extracted from the 4Mb.
For example, my mainboard can go up to 256K, if i put this card i go to 1.256k, what that means? that the 640k are available normally? and the other 600k?

3)The card I was talking about allows using a switch to operate the computer at original or dual frequency (about 8Mhz). I do not think it is too invasive as a modification, in addition to being a card designed in the 5150 sales period, it has the possibility of being disabled. Perhaps the best thing would be to get an intel xt-> 286/386 and leave the mainboard totally untouched, but I don't know if those cards are found ...

tnks

Reply 11 of 23, by chinny22

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Do you already own the Video card? If you do I'd just try it out!

I'm not one for period correct but did have similar thoughts when restoring my very first PC. (486) Finding the the balance between upgrades and original is a personal choice.
For me CPU, Sound, Floppy (for the sound at boot) all remained even though I had better options.
HDD and RAM I felt were acceptable upgrades.

Reply 12 of 23, by Thallanor

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I bought an IBM 5150 a few months ago but have only recently started working on it. Much like you, I needed/wanted to upgrade a couple components in order to make the PC a little easier to use. For me, the biggest issue was the video card, as I do not have much room, so my monitors are LCD. For this reason, I went with a Tseng ET3000AX that was listed on eBay as pulled from a 5150. (I have an ATI VGA Wonder which is supposed to work too, but my monitors would always show no signal. The card is known to work in a 386 I own.) VGA came out shortly after the end of 5150 production so it's not exactly period, but it solved a big issue for me.

I also went with an XT IDE to allow the use of CF cards. One thing that I was aware of going into this based on past experiences and is even more an issue here is to keep partition sizes small. Doing a DIR and waiting a minute to display the free disk space gets old. 😀 I have an old 1 GB card I split up a bit, and I know I have even smaller ones... somewhere. 😀

My 5150 came with 256K RAM, but I wanted to go higher. Fortunately, I found an AST SixPakPlus w/ 384K RAM on eBay - same seller, completely by coincidence, as the person I got the video card from. I also trusted it more since it was also pulled from a 5150, plus the seller was here in Canada, and he was quick to answer questions.

I decided against a sound card, simply because they didn't really become a thing until a year or two after the 5150 ended production. That being said, the Covox Speech Thing is something I am considering, as there was a little bit of overlap there, though not much. I'm still on the fence with this. I am also without a parallel port at the moment (even though the SixPakPlus comes with RTC, serial ports, parallel ports) because like you, I'm out of ISA slots - even blanks where I could just stick the port. I might remedy this by replacing my XT IDE with one that has the CF slot built-in. (Currently, I'm running an XT IDE, then a second slot for the CF slot, connected by ribbon cable.)

I originally wanted a network adapter, just to facilitate transfer of software, but with the CF card slot on the back, it makes it so easy to just eject it and then copy things on my main PC.

So that's a little feedback based upon my similar experiences. 😀

Reply 13 of 23, by Jo22

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Personally, I think you should/can be relaxed when it comes to the XT platform.
It was the platform that needed upgrades so badly, because the default configuration was extremely nerve-wracking.

Hence, upgrades were very, very common.
In fact, a few years later, no one with his/her/them right mind would have used it in its original factory configuration.
Here's a document from '85 that described memory expansion beyond 700KB, for example.

(Perhaps the original 5150 was the slowest 808x platfrom ever, right after the Sanyo MBC-550.. 😉)

Long story short: Follow your heart and don' t get distracted by today's view of history all too much, as it might be turn out wrong, anyway, since it is an idealized view.
Instead, have a look at old documents, magazines, and their reader's comments in the comments and buy/sell sections and have your own opinion. As long as the upgrades are reversible, everything will be fine.

Just be "careful" with modern additions, as they use different technology (3.3v logic instead of 5v, for example. Or CMOS instead of TTL or NMOS).
That being said, they should work fine by 99% still and usually don't cause any harm.
However, the differences should be kept in mind for troubleshooting.

Edit: AdLib and Gameblaster should be perriod-correct, as well.
About any computer game player having an XT at the time
was interested in an upgrade over the beeps and boops of the PC speaker.
Also, these devices likely required very little computing power and bandwith. Even less than the PC-Speaker, likely. 😃

Edit: The NEC chips will also boost DIR command in MS-DOS 5 and 6.x if a large HDD is installed.
With an 8088, you will need FASTOPEN or other tricks to accelerate the command.

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In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 14 of 23, by AlessandroB

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Thallanor wrote on 2020-08-17, 17:02:
I bought an IBM 5150 a few months ago but have only recently started working on it. Much like you, I needed/wanted to upgrade a […]
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I bought an IBM 5150 a few months ago but have only recently started working on it. Much like you, I needed/wanted to upgrade a couple components in order to make the PC a little easier to use. For me, the biggest issue was the video card, as I do not have much room, so my monitors are LCD. For this reason, I went with a Tseng ET3000AX that was listed on eBay as pulled from a 5150. (I have an ATI VGA Wonder which is supposed to work too, but my monitors would always show no signal. The card is known to work in a 386 I own.) VGA came out shortly after the end of 5150 production so it's not exactly period, but it solved a big issue for me.

I also went with an XT IDE to allow the use of CF cards. One thing that I was aware of going into this based on past experiences and is even more an issue here is to keep partition sizes small. Doing a DIR and waiting a minute to display the free disk space gets old. 😀 I have an old 1 GB card I split up a bit, and I know I have even smaller ones... somewhere. 😀

My 5150 came with 256K RAM, but I wanted to go higher. Fortunately, I found an AST SixPakPlus w/ 384K RAM on eBay - same seller, completely by coincidence, as the person I got the video card from. I also trusted it more since it was also pulled from a 5150, plus the seller was here in Canada, and he was quick to answer questions.

I decided against a sound card, simply because they didn't really become a thing until a year or two after the 5150 ended production. That being said, the Covox Speech Thing is something I am considering, as there was a little bit of overlap there, though not much. I'm still on the fence with this. I am also without a parallel port at the moment (even though the SixPakPlus comes with RTC, serial ports, parallel ports) because like you, I'm out of ISA slots - even blanks where I could just stick the port. I might remedy this by replacing my XT IDE with one that has the CF slot built-in. (Currently, I'm running an XT IDE, then a second slot for the CF slot, connected by ribbon cable.)

I originally wanted a network adapter, just to facilitate transfer of software, but with the CF card slot on the back, it makes it so easy to just eject it and then copy things on my main PC.

So that's a little feedback based upon my similar experiences. 😀

Thanks for your experience, what stop me now is the fact that mine board come with only 64kb of ram.

Reply 15 of 23, by waterbeesje

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AlessandroB wrote on 2020-08-17, 19:44:

Thanks for your experience, what stop me now is the fact that mine board come with only 64kb of ram.

Expansion boards usually can be set up to support existing ram from 64 to 512kB, set by jumpers for offset. Just take care for which you pick and look it up on TH99 for easy setup
In my stack of untested stuff there is an expansion card named Persyst PC/SM (not on th99 unfortunately). It should get any PC and XT compatible up to the max of 640kB with the right amount of dip chips (64kx1 and 256kx1)

Also, didn't the 5150 have sockets to upgrade to at least 256kB? 64kx1 chips (often named 4164 dram, 16 pins) are easily found, anything 150ns or faster is usually ok for a 5150.

Stuck at 10MHz...

Reply 16 of 23, by Thallanor

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AlessandroB wrote on 2020-08-17, 19:44:

Thanks for your experience, what stop me now is the fact that mine board come with only 64kb of ram.

Much like waterbeesje said, I think you'll be able to find solutions. I know that since I bought my AST SixPakPlus, I've seen other 8-bit memory boards that claim to host up to a full 640K of RAM. You might also be able to populate your motherboard to at least 256K, using more or less off the shelf chips, and then use something like the SixPakPlus (or a myriad of other boards) that might not do 640K, but do 384K, and combined with a maxed-out motherboard, bring you up to 640K. I am absolutely exhausted right now, but seem to recall that you _might_ need a newer BIOS to support some things (in fact, I'm trying to remember if the XT-IDE was one of those things requiring the latest...) but I've seen people offering to prepare ROM chips for others on request. You definitely have options. It's a fun little (big) computer. 😀

Reply 17 of 23, by pentiumspeed

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People wanted to have hercules compatiblity so they put one in XT or 286 just to game and better resolution.

Great Northern aka Canada.

Reply 18 of 23, by AlessandroB

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waterbeesje wrote on 2020-08-18, 09:31:
Expansion boards usually can be set up to support existing ram from 64 to 512kB, set by jumpers for offset. Just take care for w […]
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AlessandroB wrote on 2020-08-17, 19:44:

Thanks for your experience, what stop me now is the fact that mine board come with only 64kb of ram.

Expansion boards usually can be set up to support existing ram from 64 to 512kB, set by jumpers for offset. Just take care for which you pick and look it up on TH99 for easy setup
In my stack of untested stuff there is an expansion card named Persyst PC/SM (not on th99 unfortunately). It should get any PC and XT compatible up to the max of 640kB with the right amount of dip chips (64kx1 and 256kx1)

Also, didn't the 5150 have sockets to upgrade to at least 256kB? 64kx1 chips (often named 4164 dram, 16 pins) are easily found, anything 150ns or faster is usually ok for a 5150.

yes, my board is the one that come with 64kb but can reach up to 256k, can you suggest me the chip i need?

I have also the last bios already on the board, in fact my board is the last model build, ready for ide-xt and some cga-ega-vga card.

Reply 19 of 23, by Unknown_K

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I stuck a CGA card in my early 5150 64K board because I have a couple CGA monitors (the original MDA is on the shelf).

My unit came with a Monet Carlo RAM serial card with the same black wide bracket used on IBM original PC cards.

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